_________ a certain doubt among the people as to the practical value of the project．
| A．It has | B．It remains | C．They have | D．There remains |
________ seems to be a strong competition in China for senior high students to enter college or university.
| A．It | B．This | C．That | D．There |
It is no use _________ to persuade him ________ smoking because he has been addicted to it since he was
young.
| A．trying, to quit | B．to try, to quit | C．to try, quit | D．trying, quit |
I would have come earlier, but I ________ that you were waiting for me.
| A．hadn’t known | B．didn’t know | C．would have known | D．haven’t know |
five hours to the meeting, David learnt that it had been postponed.
| A．Having driven | B．Driven | C．Being driven | D．To be driven |
9After the new technique was introduced，the factory produced ________ tractors in 1988 as the year before.